Preparation of alkoxy- and/or halosilane (poly)sulfides and coupling agents comprised thereof

Abstract

At least one (poly)thio alkoxy and/or halosilane is/are prepared by reaction of at least one sulfur-containing reagent with at least one alkoxy and/or halosilane, wherein an ionic addition of a sulfur-containing reagent to an alkoxy and/or halosilane is preferably conducted with thermal and/or actinic activation; the novel polythio alkoxy and/or halosilanes of formula (III.2) thus prepared are particularly useful as coupling agents in elastomeric compositions containing a white filler of the silica type and having the formula (III.2) wherein, for example, R 1.1 and R 1.3 =methyl and R 1.2 =ethoxy.

1. A process for the preparation of at least one alkoxy-and/or halosilane (poly)sulfide, comprising reacting, via an ionic addition mechanism, at least one sulfur-containing reactant (Rs) with at least one alkoxy-and/or halosilane of formula (I): 
       
         
           
           
               
               
           
         
       
       in which:
 the R 1  symbols, which may be identical or different, are each:
 a linear, branched or cyclic alkyl radical having from 1 to 20 carbon atoms, 
 an aryl radical having from 6 to 18 carbon atoms, 
 an —OR 2  alkoxy radical, wherein R 2  is a linear, branched or cyclic alkyl radical having from 1 to 20 carbon atoms or an aryl radical having from 6 to 18 carbon atoms, 
 an arylalkyl radical or an alkylaryl radical (C 6 -C 18  aryl, C 1 -C 20  alkyl), 
 a hydroxyl radical, 
 or a halogen, 
 
 with the proviso that at least one of these R 1  radicals is —OR 2 , —OH or a halogen and such R 1  radicals, when they are neither hydroxyl nor halogens, optionally bear at least one halogenated substituent; 
 
       the Y symbol has the formula (II): 
       
         
           
           
               
               
           
         
       
       in which:
 the R 3  and R 4  symbols, which may be identical or different, are each hydrogen or a monovalent hydrocarbon radical selected from the group consisting of a linear, branched or cyclic alkyl radical having from 1 to 20 carbon atoms and a linear, branched or cyclic alkoxyalkyl radical having from 1 to 20 carbon atoms; 
 the R 5  symbol is CH 2  or CR 6 R 7 , wherein R 6  and R 7 , which may be identical or different, are each hydrogen or a monovalent hydrocarbon radical selected from the group consisting of a linear, branched or cyclic alkyl radical having from 1 to 20 carbon atoms and a linear, branched or cyclic alkoxyalkyl radical having from 1 to 20 carbon atoms; and 
 the n symbol is an integer greater than or equal to 1. 
 
     
     
       2. The process as defined by  claim 1 , wherein at least one of the R 1  radicals is —OR 2 . 
     
     
       3. The process as defined by  claim 1 , wherein Y has the following formula (II.1): 
       
         
           
           
               
               
           
         
       
       in which:
 the R 3  and R 4  symbols, which may be identical or different, are each hydrogen or a monovalent hydrocarbon radical selected from the group consisting of a linear, branched or cyclic alkyl radical having from 1 to 20 carbon atoms and a linear, branched or cyclic alkoxyalkyl radical having from 1 to 20 carbon atoms; 
 the R 5  symbol is CH 2  or CR 6 R 7 , wherein the R 6  and R 7  symbols, which may be identical or different, are each hydrogen or a monovalent hydrocarbon radical selected from the group consisting of a linear, branched or cyclic alkyl radical having from 1 to 20 carbon atoms and a linear, branched or cyclic alkoxyalkyl radical having from 1 to 20 carbon atoms. 
 
     
     
       4. The process as defined by  claim 1 , wherein R 4  is H and R 5  is CH 2  and the ionic addition of (Rs) takes place on the β carbon of the alkoxy-and/or halosilane (I). 
     
     
       5. The process as defined by  claim 1 , wherein R 4  is an alkyl radical, and R 5  is CH 2  and the ionic addition of (Rs) takes place on the β carbon of the alkoxy-and/or halosilane (I). 
     
     
       6. The process as defined by  claim 1 , wherein R 4  is H and R 5  is CR 6 R 7 , in which R 6  and R 7  are each —CH 3 , and the ionic addition of (Rs) takes place on the γ carbon of the alkoxy-and/or halosilane (I). 
     
     
       7. The process as defined by  claim 1 , wherein (Rs) is selected from the group consisting of HS x H, O,O′-dialkyl dithiophosphate (HSPS), M′ 2 S x , in which M′ is an alkali metal, xS, H—S x  and mixtures thereof, and the x symbol is an integer or fractional number ranging from 1 to 10. 
     
     
       8. The process as defined by  claim 1 , wherein (Rs) is O,O′-dialkyl dithiophosphate (HSPS) or HSH and the product of the reaction from (I) and (Rs) is reacted with a secondary sulfur-comprising reactant (Rs2) selected from the group consisting of S x  and/or X1S—SX2, in which X1 and X2 are a halogen and the x symbol is an integer or fractional number ranging from 1 to 10, this secondary sulfurization optionally being carried out in a basic medium. 
     
     
       9. The process as defined by  claim 1 , wherein the (I)/(Rs) molar ratio ranges from 5 to 0.1. 
     
     
       10. The process as defined by  claim 1 , wherein the ionic addition is carried out under an inert atmosphere and/or in the presence of solvent(s) selected from the group consisting of unreactive hydrocarbon solvents and aromatic hydrocarbons devoid of carbonyl or hydroxyl functional groups. 
     
     
       11. The process as defined by  claim 1 , comprising at least one hydrolysis stage to convert at least one of the R 1  radicals corresponding to —OR 2  of the alkoxy-and/or halosilane (poly)sulfide to a hydroxyl group.